Electronic component packages capable of environmentally sealing a transistor or other electronic element in an enclosed air chamber are well known in the prior art. These packages typically use alumina (Al.sub.2 O.sub.3) or beryllia (BeO) as the insulating medium and a copper alloy as the conductor terminals. Typical construction consists of an alumina or beryllia body to which copper terminals are affixed by adhesive or other bonding means, with the electronic components being attached to the conductor terminals by gold bonding wires. A cap member is placed over and cemented to the ceramic body and terminal assembly, thus providing an environmentally sealed space in which the electronic element can function optimally. Such packages advantageously have the capability to withstand the high temperatures involved in automated circuit board preparation and soldering operations, as well as the ability to tolerate long term exposure to atmospheric pressure changes, temperature variations and humidity fluctuations.
However, one significant disadvantage of using alumina or beryllia, is that both of these materials are very expensive to process and manufacture to the desired form. Additionally, precise patterns are required in achieving a connection between the electronic components and the printed circuit boards, which connection must pass either around or through the ceramic substrate. By solving the problem of the connection in this way, the path length and hence, parasitic capacitance and inductance is increased. Yet another problem in prior art ceramic transistor packages, is the difficulty involved in precisely fabricating ceramic structures of small size, which precision is critical in making the package environmentally sealed. For all the above reasons, the cost and complexity of the prior art ceramic packages is very high, i.e., these packages suffer from what can be termed an economic manufacturability problem. See e.g., U.S. Pat. No. 3,784,884 to Zorogluu, and U.S. Pat. No. 3,936,864 to Benjamin.
The realization of the need for a lower cost, easier to manufacture packages for electronic components was felt as early as 1972 as demonstrated by the above-mentioned two patents. In this regard, a very low cost packaging method has been in wide use and consists of encapsulating an entire electronic component and bonding wire/terminal connections in an insulating plastic such as epoxy. This method, although inexpensive, is not suited for applications which required higher frequencies or lower signal loss.
Thus, it can be seen that while each of the prior art devices offer some advantages, they are outweighed by the various disadvantages discussed above.